Waaree Energies Ltd. is the flagship company of Waaree Group, founded in 1989 with headquarters in Mumbai, India. It has India’s largest Solar PV Module manufacturing capacity of 2.0 GW’s at its plants in Gujarat. Waaree Energies is amongst the top player in India providing EPC services, project development, rooftop solutions, and solar water pumps and also as an Independent Power Producer. Waaree has its presence in over 300+ locations nationally and 68 countries internationally. Waaree Energies which has a major focus on solar PV module manufacturing has recently also ventured into Lithium Ion battery manufacturing making it the country’s largest vertically integrated energy company. Waaree Energies offer solar PV modules right from 3 Wp to as high as 400 Wp. The major variants comprise of multi/poly crystalline modules, mono PERC modules, AC modules, flexible modules, half cut cell based modules and bifacial modules.
Solar modules have predominantly used both on land and at the top of the industry/home/commercial roofs. In the run of minimizing the LCOE while also parallelly maximizing the commercial gains from a solar power plant, the shift to highly efficient modules with enhanced technical advantages is the need of the hour. So a novel design module utilizing a new cell technology was developed. The cells used were based on large full square mono wafers i.e. 158.75 mm (generally known G1 size).
Further, the upgraded design of the solar PV module utilized half cut cells instead of full cells. These half cut cells were not all inter-connected in series but a set of series connected half cut cells were interconnected in parallel with other which helped to achieve a maximum power of 400 Wp. To simplify, these module consist two modules of half cut cells connected in parallel with each other. It is the first product with such power output in Indian PV market (Figure 1). The modules are available in 2 variants mono facial (Super 400) and Bifacial variant (Super 400 Pro), whose technical advantages are mentioned as below.
Significant reduction in resistive losses
The current output from a solar cell is dependent on the number of light particles (photons) falling on it which further depends on the area of the cell. Thus increasing the area of cell directly increases the current output of solar cell. The Super 400 series modules use half cut cells which directly halves the current output from the cell. The resistive power loss in a module is directly proportional to the square of the current flowing through (or generated by) the cells. Halving the current reduces the resistive losses (I2R) of the module by one fourth as shown in figure 2. Primarily this reduction in resistive losses directly reduces the nominal module operating temperature (NMOT). Further, such decrease in the resistive losses directly leads to an increase of efficiency of module by around 1%. Additionally, such gain is improved significantly with increase in irradiance as the current output of the module is directly proportional to the irradiance.
Advantages of enhanced design
The constructional changes of the half cut cell based Super 400 modules are numerous. This module has increased open area when compared to the traditional module. This allows more light to be reflected into the module from the backsheet which enables enhanced power generation from the module. Additionally, compared to the traditional modules, the excited electrons in this module have to travel almost half the distance before they are connected at the module’s junction box (JB). Comparing to traditional module, the electron faces less resistance which further increases the power output of the module (refer to Figure 3).
Better performance in shade
The solar modules are installed in such a way that their generation is not hampered by shadow at any point of time. However within its lifetime of 25 years, there may be times when a module or the string experiences shadow. Such shadow may be due to many reasons such as expansion of nearby building, shadow due to nearby trees, bird shit, cloudy atmospheric conditions etc. which may be temporary, for few hours or days or even permanent. Shadow even if on any cell(s) in the string hampers the generation of the string and hence the solar module. Under normal operation, both the traditional and Super 400 module produces the desired power output. But when all the strings of the traditional module are under shadow all 3 bypass diodes of the module are activated resulting in zero power output from the module. Whereas in case of Super 400 module, the bypass diode is in between the two strings of upper and lower half of module. While the lower half is under shadow, the upper half of the module is continuously generating power. Hence, 50% of power under shadow conditions is retained as shown in figure 4.
Advantages of using split junction box
A junction box (JB) houses electrical interconnection within the string of the module. It also houses bypass diode(s) (reverse biased) which protects the module from generating hotspot in case of shadow. The Super 400 series module utilizes a split type junction box as shown in figure 5 below. A typical split type JB consists of three separate boxes collecting current from separate strings. This primarily leads to better dissipation of heat from the JB. Also as discussed in previous section, the Super 400 module keeps performing even when in shade. This enables the bypass to be less active as compared to traditional modules. This could overall enhance the life of the bypass diode and further the solar module.
Waaree Energies have understood the advantages of half cut cell module and have introduced their half cut based doublet module both in mono/multi crystalline and PERC based solar cells. With the given advancements in solar module technology, we believe that it’s time when the end customer gets the maximum energy output. Additionally, our stringent quality checks also ensures that the reliability of the module is not compromised at any stage in manufacturing or when performing in the field.
Let us all pledge to make solar energy the primary source of energy in the near future.
RAHE ROSHAN HAMARA NATION